SIP Features:

* RFC3261, RFC3262, RFC3666, RFC2543 .

* Proxy and Register.

* SIP domain .

* Server authentication: none,basic,MD5.

* DNS name of SIP server .

* SIP signaling port setting .

* NAT transverse,STUN.

* NAT transverse ,SIP Express router.

* Public Server /Private server ,Can connect to ISP and Private SIP server at same time .

* Dual public server .

* SIP Call forward /transfer/ holding/waiting .

* Peer to peer SIP call .